Manufacture of artificial silk.



K Drawing.

subject of UNITED STATES PATENT OFFICE.-

HEBMAN TIKPE, OF AMSTERDAM, NETHERLANDS, "ASSI'GN'OB '10 JIAAMLOOZE VEN-N'OOTSGHAP HOLLANDSGHE ZIJDE MAATSCHAPPIJ, 0E AMSTERDAM, NETHER- LANDS,A COMPANY OF THE I MANUFACTURE O1? ABTIFI CIAL SILK.

I To alt whom it may concern:

' Be it known that I, HERMAN Tmrn, a

the Emperor of. Germany, residmg at Weesperz'ijde No. 125, Amsterdam,Province ofNoord, Kingdom of the Iletherlands, have invented certain newand useful Improvements in and Relating to the Manufacture of ArtificialSilk, of which the following is a specification.

This invention relates to the manufacture of artificial silk from milkand particularly to the process in which the albumins of the milk aredecomposed by the action of a salt of pyrophosphoric acid. I

Previous attempts to produce from albuminous substances silk-likethreads having similar qualities to the ordinary animal product have hadbut little success. The most comprehensive experiments in thisconnection have been on casein preparations and the product obtained wasalways hard and brittle, fine threads such as are necessary for theproduction of a good silk not being possible of production. It is truethat a certain amount of flexibility could be given to the product bymeans of chemical additions such as glycerin or the like but this isonly at the cost of strength. Casein products cannot therefore beconsidered to have previously yielded really silk-like threads. Myinventionis distinguished from the methods heretofore employed, in thatit does not use casein as a starting material, but instead employs as araw material the protein substances which remain in cows milk after thesame has been reacted on by salts of pyrophosphoric acid orpyrophosphates, and the casein precipitated thereby has been removedtherefrom. The protein substances left in the whey after the removal ofthe casein thus precipitated, consist in lactals bumin and a derivativeproduct of casein. These protein substances are then thrown out from thewhey by means of such reagents as are ordinarily used ing casein andalbuminates. The product thus precipitated is then rendered plastic bythe addition of a small amount of ammonia or other alkali, whereupon thesame may be worked into the finest silk-like threads which are elastic,and which possess also great strength and great toughness, therebyadapting them in a marked degree for all purposes where silk isemployed.

I Specification 6: Letters Patent. Application filed June 17, 1911.Serial il'o. 633,786.

in precipitat- 7 Patented Feb. 17', 1914;

The following example servesto disclose my lnventlon in detail:

A' solution of a pyrophosphoric salt is slowly added to milk, referablyskim milk,

for example,.to each iter of milk at, least threegms. of dry sodiumpyrophosphate or the equlvalent amount of another pyrophosphate. Themilk curdles and forms at first 1nto a elly-like mass. After standingfor a short time, especially in a heated, condition, .the solidmaterials separate out sufliciently from the whey so that a separationof the two is possible. The albuminous'substance 111 solution in thewhey is separated out therefrom by means of diluted acids or other knownprecipitating agents, and after the liquid present has been pressed outthe product is converted into a tough plastic mass by adding a smallamount of ammonia or other alkali. If the material is to be made intothreads the albumin precipitated out by the acids is first washed withwater and then again dissolved completely in diluted alkali lye,whereupon the solution is filtered and the product precipitated out bydilute acids.

The product purified in this manner is freed from moisture by pressingand then converted into the plastic form by means of ammonia or otheralkali. This material which can .be drawn out into the finest threads,is

worked in known manner and hardened by the action of formaldehyde orother known hardening agent.

By applicants process which involves the treatment of the whey leftafter reaction on the milk with a salt of pyrophosphoric acid, quite adifferent precipitation from that which is usually carried out by meansof acid, occurs in the milk. When a. solution of such salt ofpyrophosphoric acid is added to the milk, I find that a voluminousprecipitate is formed, the casein thrown down acid assumes a flockyincoherent form, I

whereas when precipitated according to this invention the casein assumesthe form of a glutinous and stringy mass which can be drawn out intothreads. The whey left after the removal of this precipitatecontamslactalbumin and a derivative product of casein and this product hasessentially different properties from the original casein; Thus, forexample it contains no paracasein, a body which is always thrown ,downwhen ordinary milk is treated with rennet ferment and which is acharacteristic product i when casein of ordinary milk is treated withrennet ferment.

What I claim is 1. The process which consists in adding a pyrophosphateto milk, removing'the resultant precipitate of casein, thenprecipitating the protein substances from the remaining liquid andtreating them with alkali for'the purpose of forming them into a plasticmass.

2. The process which consists in adding a pyrophosphate to milk,removing the resultant precipitate of casein, then precipitating theprotein substances from the remaining liquid and dissolvin the same inan alkali solution, then reprecipitating them with dilute acid.

3. The process which consists in adding a pyrophosphate to milk,removing the resultant precipitate of casein, then precipitating theprotein substances from the remaining li uid and dissolvin the same inan alkali so ution, then repreclpitating them with dilute acid, and thentreating with alkali to form the same into a plastic mass.

4. The process which consists in adding a pyrophosphate to milk,removing the resultant precipitate of casein, then precipitating theprotein substances from the remaining li uid and dissolving the same inan alkali so ution, then reprecipitating them with dilute acid, thentreating with alkali to form the ,same into a plastic mass, and thendrawing the mass out into threads and hardening the threads.

5. The process which consists in adding a pyrophosphate to milk,removing the resultant precipitate of casein, then precipitating theprotein substances from the remaining li uid and dissolving the same inan alkali so ution, then repreclpitating them with dilute acid, thentreating with alkali to form the same into a plastic mass and thendrawing the mass out into threads and hardening the threads by treatingwith formic aldehyde.

6. As a new albuminous product, a thread formed from a plastic massconsisting of lactalbumin and a casein'derivative containing noparacasein.

7. As a new albuminous product, a thread consisting of a thread formedfrom a plastic protein mass formed from whey remaining after reacting onmilk with a salt of pyrophosphoric acid with a coagulating agent, saidmass consisting of lactalbumin and a casein derivative containing noparacasein.

In testimony whereof I have hereunto set 05 my hand in presence of twosubscribing witnesses.

HERMAN TIMI E.

Witnesses:

THOMAS HoLIHAN, D. P. DE YOUNG.

